In this image from May 22, Red Cross Kumamoto Hospital workers help patients and colleagues sickened by toxic fumes released as they treated a Japanese farmer who committed suicide by drinking pesticide. As doctors tried to pump the 34-year-old man's stomach, he vomited, spraying the medical personnel with chloropicrin. Fifty-four doctors, nurses and patients developed breathing problems and 10 of them were hospitalized.

By Paul Wiseman, USA TODAY

TOKYO  A suicide fad is sweeping Japan: Hundreds of Japanese have killed themselves this year by mixing ordinary household chemicals into a lethal cloud of poison gas that often injures others and forces the evacuation of entire apartment blocks.

The 517 self-inflicted deaths by hydrogen sulfide poisoning this year are part of a bigger, grimmer story: Nearly 34,000 Japanese killed themselves last year, according to the Japanese national police. That's the second-highest toll ever in a country where the suicide rate is ninth highest in the world and more than double that of the USA, the World Health Organization says.

Japan has long been known as a "nation of suicide," notes sociologist Kayoko Ueno at University of Tokushima. Samurai warriors famously chose seppuku — disemboweling themselves — over surrender. Japanese kamikaze pilots crashed their planes into targets during World War II.

"Suicide is not considered a sin," says sociologist Masahiro Yamada of Chuo University in Tokyo. "We've made it a bit of a virtue."

Authorities are alarmed now that suicide has reached epidemic levels. Reasons:

• A decade of weak economic growth and the unraveling of Japan's system of lifetime employment have left many middle-age and elderly men unemployed and in financial ruin. Among Japanese suicides, nearly 71% are men, more than 73% are 40 or older, and more than 57% are jobless.

For an unemployed, former "salaryman," suicide can be "a rational decision," Yamada says. When a man commits suicide in Japan, his beneficiaries can still collect his life insurance. And insurers pay off Japanese home mortgages when a family's breadwinner dies — even if the death is a suicide. "If he dies, the rest of the family gets money," Yamada says. "If he continues to live without a job, they will lose the house."

• The Internet has allowed young, depressed Japanese to get suicide tips and find others with whom they can enter into death pacts.

A few years ago, suicidal Japanese were meeting each other online, driving out into the countryside, shutting themselves up in the back of vans and killing themselves in clouds of carbon monoxide by burning charcoal briquettes. "People really want to be connected. People got together to die," says anti-suicide activist Koji Tsukino, 43.

Tsukino, a recovering alcoholic and drug user who tried to kill himself 10 times before he turned 30, says the latest suicide craze is even scarier than those in the past.

Hydrogen sulfide is dangerous even to those who don't want to kill themselves. The toxic gas can carry into neighboring buildings and apartments. In April, 80 people were injured and another 120 had to be evacuated after a 14-year-old girl killed herself with hydrogen sulfide in southern Japan's Kochi prefecture. She'd left a note on the door of her family's apartment that said, "Gas being emitted. Don't open," according to the Kyodo news service.

Police have asked Internet service providers to ban websites that promote suicide — but with only mixed success.

"If just one person decided not to do it, that would be great," Tsukino says. "They might go on to get married and have children."

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